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1. An atom has 19 protons and 20 neutrons. How many electrons are there?

Answer:

The sequence of individual steps, or elementary reactions, by which reactants are converted into products during the course of a reaction is called the reaction mechanism. The overall rate of a reaction is determined by the rate of the slowest step, called the rate-determining step.

Explanation:

Answer:

The loosening of soil and they bind the soil with the help of the roots

Explanation:

Here, we want to know how plants prevent erosion by wind or water.

The way they do this is by binding the soil with their roots such that it will not be easy for the erosion agent to erode the surface.

How they do this is by making sure that the soil

particles are binded together with their roots which helps to keep the particles of the soil intact and not eroded

Answer:

c

Explanation:

Answer:

flows through your viens and moves to your blood vesils

Explanation:

its how blood operates

Answer:

Lithium sulfide

Answer: 25 + 27 + 29 = 81

81 divided by 3 = 27

your answer is 27

Explanation: you add them all together then however many numbers there are is how you divide it

Answer:

81 and 27 i think

Explanation:

Answer:

Its a

Explanation:

I got that answer on my own not from the Question ;)

One s-orbital is present in each sublevel of the primary energy level. There are 2 electrons in the s-orbital in total. When compared to other primary energy levels, the electrons in this orbital, known as s electrons, have the lowest energy. Here the correct option is A.

The fixed distances from an atom's nucleus where electrons may be found are referred to as energy levels (also known as electron shells). In an atom, the small, positively charged nucleus is surrounded by smaller, negatively charged electrons.

One s-orbital, three sets of p-orbitals, and five sets of d-orbitals make up the subshell of the third main energy level. S-orbitals can store a maximum of two electrons, p-orbitals six, and d-orbitals ten. One s-orbital is present in each sublevel of the primary energy level. There are 2 electrons in the s-orbital in total.

Thus the correct option is A.

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Answer:

i think that the answer is B

Explanation:

If a student wants to investigate competition between two organisms in an ecosystem the organisms should have same adaptations and use same resources.

Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.

Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.

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Answer:

CH4

- 4 electron

- 0 electron

- the geometry of Ch4 is tetrahedral

AlF3

- 3 electron

- 0 electron

- the geometry is trigonal planar

CCl4

- 4 electron

- 0 electron

- the geomotry is tetrahedral

SeH2

- 2 electron

- 2 electron

- the geometry is V shape

Answer:

Reactants, Activation energy, Energy released by the reaction and Products

Explanation:

This energy profile is that of an exothermic reaction. In an exothermic reaction, heat is liberated to the surrounding. The surrounding becomes hotter than the environment.

The first box to the left is the reactants which signifies the species combining together.

The topmost box is the activation energy which is the energy barrier that must be over come before a reaction takes place.

The box underneath is the energy change. Here, energy is being released.

The right most box is the product of the reaction.

Answer:

wavelength = wave velocity/frequency.

Explanation:

c

 is a constant. It is usually given as

3.00

×

10

8

m/s or

3.00

×

10

10

cm/s rounded to three significant figures.

Wavelength is measured in meters, centimeters, nanometers, etc...).

Frequency has a unit of

1/s

which means

1

cycle per second. It is also given the unit Hertz (Hz) in honor of German physicist Heinrich Hertz who proved the existence of electromagnetic waves.

1

Hz

=

1/s

.

Answer:

The basic metal ones?

Explanation:

...

Answer:

Yes!

Explanation:

Liquids & gases are poor conductors, but they can make heat (thermal energy) travel quickly from one point to another. ... ~ When waves of heat (thermal energy) travel through empty space and transparent mediums, heat transfer by radiation occurs. Solids, liquids, & gases can all be heated by radiation.

Answer:it’s c

Explanation:

Edge 2021

Answer:

Explanation:

To determine the melting point of the unknown white substances. A sample of each of the unknown can be placed in separate capillary tubes and then placed in an adjustable heat source (for example water bath). A thermometer is then placed in the heat source very close to the tube holding the sample. The temperature of the heat source will be adjusted until the solid substance in the capillary tube starts to melt, the temperature at this point is noted as the melting point.

To determine the conductivity of the white substances, an electrolysis experiment is done. A sample each of the unknown substances is dissolved in water. These aqueous solutions are prepared separately. Two electrodes (positively charged anode and negatively charged cathode) are dipped into each of these solutions and an electric current is passed through these solutions, from an energy source (such as batter), through the electrodes (with the electric current flowing from the anode to the cathode). A voltmeter is then connected to this set-up to determine if electricity is been passed through the individual solutions.

The substance that is the salt will be the white substance that has the higher melting point and conducted electricity in the electrolysis set up; this is because NaCl salt is an ionic compound which has a high melting point and conducts electricity when dissolved in water. While the white substance that had a lower melting point and did not conduct electricity will be the sugar; this is because sugar/sucrose is an organic substance that has a low melting point and does not conduct electricity when dissolved in water.

Answer:

4.97 moles

Explanation:

There are  6.022*10^23 calcium  atoms  in 1 mole of  Ca

2.99*10^24/6.022*10^23

=4.97 moles

Answer:

4.97 mol

Explanation:

Given data:

Number of atoms of Ca = 2.99×10²⁴

Number of moles of Ca = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.  The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

2.99×10²⁴  atoms × 1 mol  / 6.022 × 10²³ atoms

0.497×10¹ mol

4.97 mol

Answer:

0.385 J/g°C

Explanation:

Using the following formula, the specific heat of an elemental substance can be calculated:

Q = m × c × ∆T

Where;

Q = quantity of heat (J)

m = mass (g)

c = specific heat capacity (J/g°C)

∆T = change in temperature (°C)

Based on the given information, Q = 1375J, m = 50g, initial temperature = 22.8°C, final temperature = 94.2°C, c =?

Q = m × c × ∆T

1375 = 50 × c × (94.2 - 22.8°C)

1375 = 50 × c × 71.4

1375 = 3570c

c = 1375/3570

c = 0.3851

c = 0.385 J/g°C

Answer:

Sonoluminescence can occur when a sound wave of sufficient intensity induces a gaseous cavity within a liquid to collapse quickly. [...] The bubbles are very small when they emit the light—about 1 micrometer in diameter—depending on the ambient fluid (e.g., water) and the gas content of the bubble (e.g., atmospheric air).

Explanation:

Source is Google

Answer:

24g

Explanation:

2×12=24

1mole of Mg react with 2 mooe of O2

D snails, guppies and plants. The community should be diverse and have lots of biodiversity.

Answer:

to

Explanation:

to

Answer:

Honestly no idea

Explanation:

FOOOOOOOOD

Answer:

Condenses at 27.25K.

Freezes at 24.65K.

Explanation:

In order to solve this above question, there is is need to make use of the following equation. The main idea here is to convert degree celsius to Kelvin. Hence,

0°C + 273.15 = 273.15K---------------------(1).

Therefore, we will make use of the above equation (1) and slot in the values for at degree celsius at which it condenses and at degree celsius at which it freezes.

So, we have at temperature at which it condenses:

-245.9°C + 273.15 = 27.25K.

Also, we have at temperature at which it freezes.

-248.5°C + 273.15 = 24.65K.

Answer: Lithium ( 3),Calcium (20),Copper (29),Strontium (38),Potassium (19),Sodium (11)

Explanation:

Answer:

They hatch into larvae.

Explanation:

Answer:

I really dont know i just guessed :(

Explanation:

Answer:

index of refraction

Explanation:

Answer:

550 K

Explanation:

Given the following data;

Original Volume, V1 = 20mL

Original Temperature, T1 = 200K

New Temperature, V2 = 55mL

To find new temperature T2, we would use Charles' law.

Charles states that when the pressure of an ideal gas is kept constant, the volume of the gas is directly proportional to the absolute temperature of the gas.

Mathematically, Charles is given by;

[tex] VT = K[/tex]

[tex] \frac{V1}{T1} = \frac{V2}{T2}[/tex]

Making T2 the subject of formula, we have;

[tex]T_{2} = \frac{V2}{V1} * T_{1}\\[/tex]

Substituting into the equation;

[tex]T_{2} = \frac{55}{20} * 200\\T_{2} = \frac{11000}{20}\\T_{2} = 550K[/tex]

Therefore, the new temperature is 550K.

Answer 1: The two most basic types of bonds are characterized as either ionic or covalent. In ionic bonding, atoms transfer electrons to each other. ... In contrast, atoms with the same electronegativity share electrons in covalent bonds, because neither atom preferentially attracts or repels the shared electrons.

Answer 2 : In ionic bonding, the atoms are bound by attraction of oppositely charged ions, whereas, in covalent bonding, atoms are bound by sharing electrons to attain stable electron configurations.

Answer 3 : Each nitrogen molecule consists of two atoms of nitrogen that are bonded by a triple covalent bond. This is a direct consequence of the fact that each nitrogen atom has 5 valence electrons. Each atom can thus complete its octet by sharing three electrons.

Bark bark Hope this helps :)

Answer:

O_o

Explanation:

Answer:

A

Explanation:

If there is a whole new solution, then there was definetly a Chemical Change!

~PumpkinSpice1

c is correct

Explanation: